Curiosity enhances incidental object encoding in 8-month-old infants

Recent research with adults indicates that curiosity induced by uncertainty enhances learning and memory outcomes and that the resolution of curiosity has a special role in curiosity-driven learning. However, the role of curiosity-based learning in early development is unclear. Here we presented 8-month-old infants with a novel looking time procedure to explore (a) whether uncertainty-induced curiosity enhances learning of incidental information and (b) whether uncertainty-induced curiosity leads infants to seek uncertainty resolution over novelty. In Experiment 1, infants saw blurred images to induce curiosity (Curiosity sequence) or a clear image (Non-curiosity sequence) followed by presentation of incidental objects. Despite looking equally to the incidental objects in both sequences, in a subsequent object recognition phase infants looked longer to incidental objects presented in the Non-curiosity condition compared with the Curiosity condition, indicating that curiosity induced by blurred pictures enhanced the processing of the incidental object, leading to a novelty preference for the incidental object shown in the Non-Curiosity condition. In Experiment 2, a blurred picture of a novel toy was first presented, followed by its corresponding clear picture paired with a clear picture of a new novel toy side by side. Infants showed no preference for either image, providing no evidence for a drive to resolve uncertainty. Overall, the current experiments suggest that curiosity has a broad attention-enhancing effect in infancy. Taking into account existing studies with older children and adults, we propose a developmental change in the function of curiosity, from this attentional enhancement to more goal-directed information seeking in older children and adults.

Use of Repeated Within-Subject Measures to Assess Infants' Preference for Similar Others

Research employing single-choice paradigms in which an infant is asked to make a single choice between two puppets suggest that infants show a preference for prosocial others and those who are similar to themselves. However, the extent to which infants’ preference for similar others is stable is unknown, as are other factors within the paradigm that may influence infants’ choices. The purpose of this study (two experiments, N = 44 infants, aged 8–15 months) was to replicate and extend previous work by including (1) within-subject repeated measures and (2) an experimental manipulation of a plausible demand characteristic. Results for the first-choice trial indicated a majority of the infants did not choose the similar puppet. Results from the within-subject repeated trials also indicated that a majority of the infants did not choose the similar puppet but a majority did choose a puppet from the same side. The experimental manipulation of the demand characteristic showed no effect on infant puppet choices. These results suggest that a closer examination of the single-choice puppet paradigm for assessing infants’ social evaluation is warranted. These findings also support recommendations made by others, including publishing null findings, standardizing data collection and reporting methods, and examining individual differences by employing within-subject designs with repeated measures.

Infant Visual Attention and Stimulus Repetition Effects on Object Recognition

This study examined behavioral, heart rate (HR), and event-related potential (ERP) correlates of attention and recognition memory for 4.5-, 6-, and 7.5-month-old infants (N = 45) during stimulus encoding. Attention was utilized as an independent variable using HR measures. The Nc ERP component associated with attention and the late slow wave (LSW) associated with recognition memory were analyzed. The 7.5-month-olds demonstrated a significant reduction in Nc amplitude with stimulus repetition. This reduction in Nc was not found for younger infants. Additionally, infants only demonstrated differential LSW amplitude based on stimulus type on attentive trials as defined by HR changes. These findings indicate that from 4.5 to 7.5 months, infants' attentional engagement is influenced by an increasingly broader range of stimulus characteristics.

Stability of infants' preference for prosocial others: Implications for research based on single-choice paradigms

Some research suggests infants display a tendency to judge others’ prosocial behavior, and in particular, that infants show a strong preference for prosocial others. For example, data from one frequently cited and well-publicized study showed that, after watching a puppet show with three puppets, 74% of infants chose the puppet that “helped” rather than the puppet that “hindered” a third puppet from attaining its goal. The purpose of the current investigation was to replicate these methods and extend them by including a within-subject measure of infant puppet choice across repeated trials to assess the stability of infants’ choice. In the current study, 20 infants viewed a puppet show and chose between two puppets (i.e., helper or hinderer) immediately following the puppet show. Although results were similar to previously published work on the first-choice trial (65% of infants chose the helper puppet on the first trial), infants did not consistently choose the helper across trials; several infants demonstrated a side preference, with 9 infants almost exclusively choosing puppets presented on the right or left side. The current investigation addressed limitations of previous research by including a between-subjects (replication) as well as a within-subjects (extension) repeated measure of choice that allowed for the examination of the stability of the choice measure. Our results, particularly in light of other failed replications, raise questions regarding the robustness of infants’ preference for prosocial others and the reliability and validity of the single-choice paradigm.

Contributions of Look Duration and Gaze Shift Patterns to Infants' Novelty Preferences

Data from 72 infants, tested using a serial paired-comparison paradigm, were analyzed to better understand infant novelty preferences. Infants between the ages of 15 and 26 weeks were tested in three studies with familiar stimuli displayed adjacent to novel stimuli on each trial. Differences in look duration, look number, and gaze shifts directed at novel versus familiar stimuli were assessed to measure their contributions to group and individual novelty preferences. Infants produced longer looks for novel stimuli in all three studies, and stimulus differences in look duration accounted for more than 50% of the variability in individual novelty preferences. Infants that produced more looks to novel rather than familiar stimuli did not produce overall novelty preferences unless they also looked longer at novel stimuli. Gaze shift patterns did not predict individual novelty preferences, and novel stimuli did not determine where infants looked. The infants' visual exploration was constrained by memories for the direction of the previous look as well as by the attention-holding features of novel stimuli.

Infants' ability to extract three-dimensional shape from coherent motion

Our capacity to perceive three-dimensional (3D) object structure from two-dimensional (2D) retinal input is fundamental to object perception. The present research examined infants' ability to extract 3D form from structure-from-motion (SFM) displays using a familiarization/visual-paired-comparison paradigm. In SFM displays dots are projected onto the surfaces of a shape that rotates around a 3D axis and it is the coherent structure of the dots' motion that gives rise to the percept of shape. Infants mean age 4.5 and 9 months were familiarized to a SFM display (e.g., cylinder); in test they were presented the familiar SFM display paired with a novel SFM display (e.g., cube). Infants in both age groups displayed a significant preference for the novel SFM test display. These results are consistent with those obtained previously using habituation paradigms and provide converging evidence for infants' early emerging capacity to use coherent motion - in the absence of figural information - as a cue to depth structure. In addition, these results demonstrate that infants' ability to extract 3D shape from coherent motion can be successfully assessed with a neuroimaging-friendly protocol, which was one of the goals of this study.

Autonomy in action: linking the act of looking to memory formation in infancy via dynamic neural fields

Looking is a fundamental exploratory behavior by which infants acquire knowledge about the world. In theories of infant habituation, however, looking as an exploratory behavior has been deemphasized relative to the reliable nature with which looking indexes active cognitive processing. We present a new theory that connects looking to the dynamics of memory formation and formally implement this theory in a Dynamic Neural Field model that learns autonomously as it actively looks and looks away from a stimulus. We situate this model in a habituation task and illustrate the mechanisms by which looking, encoding, working memory formation, and long-term memory formation give rise to habituation across multiple stimulus and task contexts. We also illustrate how the act of looking and the temporal dynamics of learning affect each other. Finally, we test a new hypothesis about the sources of developmental differences in looking.

Auditory-visual intermodal matching of small numerosities in 6-month-old infants

Recent studies have reported that preverbal infants are able to discriminate between numerosities of sets presented within a particular modality. There is still debate, however, over whether they are able to perform intermodal numerosity matching, i.e. to relate numerosities of sets presented with different sensory modalities. The present study investigated auditory-visual intermodal matching of small numerosities in infancy by using a violation-of-expectation paradigm. After being familiarized with events of a few objects impacting a surface successively, 6-month-old infants were alternatively presented with two and three tones while the movement of each object remained hidden behind an opaque screen. The screen was then removed to reveal either two or three objects. Results showed that the infants looked significantly longer at the numerically nonequivalent events (the three-tone/two-object and the two-tone/three-object events) than at the numerically equivalent events (the two-tone/two-object and the three-tone/three-object events) irrespective of the rate or duration of auditory tones presented. These findings suggest that infants are capable of performing intermodal matching of small numerosities and that they might possess abstract representations of numerosity beyond sensory modalities.